Welcome to HVAC-Talk.com, a non-DIY site and the ultimate Source for HVAC Information & Knowledge Sharing for the industry professional! Here you can join over 150,000 HVAC Professionals & enthusiasts from around the world discussing all things related to HVAC/R. You are currently viewing as a NON-REGISTERED guest which gives you limited access to view discussions

To gain full access to our forums you must register; for a free account. As a registered Guest you will be able to:

Participate in over 40 different forums and search/browse from nearly 3 million posts.

Is A/C compressor affected by outside temperatures?

I recently had issues with my upstairs A/C, the outside condenser unit was shutting off randomly at random times while the internal fan continues to run. (Details in this thread: http://hvac-talk.com/vbb/showthread....s-off-randomly) In a nutshell, I had the A/C tech come back out after I recorded a video of the condenser unit emitting a high pitched screeching/whine sound. He changed out the capacitor, and we were issue-free for a week.

This week though it has been not cooling yet again, however I've noticed this is a different issue:

1) Internal fan runs, and so does condenser fan but I do not hear the compressor on. When it is cooling, you can hear the compressor clearly.
2) It doesn't cool at a specific time, around 3-5pm, about half the days this week. Other times in the day have been fine.
3) It hasn't made the screeching sound again.

I feel like the compressor is starting to fail, and maybe the capacitor issues from before which affected the fan, in turn put more wear on the compressor. We have had 104-106+ high temps all week...does the compressor ever fail in relation to the outside temp?

FYI I keep it at 85 deg during the day and 78 at around 5pm. On the weekends (which has followed the afternoon failing pattern) I keep it at 78 all day.

I recently had issues with my upstairs A/C, the outside condenser unit was shutting off randomly at random times while the internal fan continues to run. (Details in this thread: http://hvac-talk.com/vbb/showthread....s-off-randomly) In a nutshell, I had the A/C tech come back out after I recorded a video of the condenser unit emitting a high pitched screeching/whine sound. He changed out the capacitor, and we were issue-free for a week.

This week though it has been not cooling yet again, however I've noticed this is a different issue:

1) Internal fan runs, and so does condenser fan but I do not hear the compressor on. When it is cooling, you can hear the compressor clearly.
2) It doesn't cool at a specific time, around 3-5pm, about half the days this week. Other times in the day have been fine.
3) It hasn't made the screeching sound again.

I feel like the compressor is starting to fail, and maybe the capacitor issues from before which affected the fan, in turn put more wear on the compressor. We have had 104-106+ high temps all week...does the compressor ever fail in relation to the outside temp?

FYI I keep it at 85 deg during the day and 78 at around 5pm. On the weekends (which has followed the afternoon failing pattern) I keep it at 78 all day.

Thanks!

The O/D ambient does have an effect on the compressor, but should not cause issues with it turning on and off.

The system may be over charged or air flow over condenser is restricted.

A lot more data would help such as voltage, amperage, pressures, temperatures etc.

Condenser fan motor stalled out, compressor went into bypass, finally cut out on internal overload...high pitched squeal afterward was bypass still open until pressures equalized a bit. Then it stopped and left you with silence.

Tech may have changed capacitor for fan motor out but the motor itself is probably bad.

Condenser fan motor stalled out, compressor went into bypass, finally cut out on internal overload...high pitched squeal afterward was bypass still open until pressures equalized a bit. Then it stopped and left you with silence.

Tech may have changed capacitor for fan motor out but the motor itself is probably bad.

Post 10,000...woo hoo!!

Hah, congrats! So, if the condenser fan is still working right now when the compressor is off (and no coolness) would this fix my current issue? And, I do plan to call a tech, I just don't want a repeat of my previous tech who was unable to diagnose anything if it was blowing cold at the moment.

Hah, congrats! So, if the condenser fan is still working right now when the compressor is off (and no coolness) would this fix my current issue? And, I do plan to call a tech, I just don't want a repeat of my previous tech who was unable to diagnose anything if it was blowing cold at the moment.

it is hard to say what is wrong with the compressor, but the individual that changed to capacitor should have taken all of the measurements and posted on his service ticket.

Hah, congrats! So, if the condenser fan is still working right now when the compressor is off (and no coolness) would this fix my current issue? And, I do plan to call a tech, I just don't want a repeat of my previous tech who was unable to diagnose anything if it was blowing cold

Often I can spot a condenser fan motor showing signs of impending death. Lateral play in the motor shaft. Amp draw excessive. Bearings feeling a bit stiff with the motor de-energized. Imbalanced fan blades. Etc. A tech need not wait for the thing to fail in order to look for these signs.

While I have seen videos of fan blades where they appear to be turning slowly due to the frame rate of the camera, in your case it was obvious the blades were not turning at all! That is NOT GOOD!

Often I can spot a condenser fan motor showing signs of impending death. Lateral play in the motor shaft. Amp draw excessive. Bearings feeling a bit stiff with the motor de-energized. Imbalanced fan blades. Etc. A tech need not wait for the thing to fail in order to look for these signs.

While I have seen videos of fan blades where they appear to be turning slowly due to the frame rate of the camera, in your case it was obvious the blades were not turning at all! That is NOT GOOD!

So to clarify, the fan is spinning well right now. The video was from the previous issue (which the capacitor fix took care of). It has not made that sound (and the fan has been working well) since the fix. If the motor is still bad, would it cause the current issue of shutting off the compressor only during a couple of the afternoon hours?